The present invention relates to a radial scan, forward viewing ultrasonic endoscope having at the tip of an insertion portion objective optics for optical examination of the area ahead of said insertion portion and an ultrasonic probe for performing radial scan by ultrasonic waves.
For ultrasonic endoscopes that can optically examine a body cavity while performing ultrasonic scan, it is generally considered advisable to project ultrasonic waves from the tip of an insertion portion to perform lateral scan as the area which lies the nearest possible to the scanning direction is being examined optically. The ultrasonic endoscopes are structurally designed to meet this requirement.
However, the greatest value of ultrasonic endoscopes lies not in obtaining an ultrasonic cross-sectional image of the other side of an abnormal area of the mucous membrane in the body cavity of interest but rather in inserting the ultrasonic endoscope into an organ adjacent the inaccessible organ and performing ultrasonic scan from that organ.
Therefore, effective ultrasonic scan is inmost cases radial scan about the longitudinal axis of the tip of the insertion portion whereas effective optical examination is forward viewing which is most convenient for checking the area ahead of the insertion portion of the endoscope as it is passed into the body cavity.
However, ultrasonic endoscopes of this type which are commonly called xe2x80x9cradial scan, forward viewing ultrasonic endoscopesxe2x80x9d have several problems to solve, such as designing a structure that can shorten the rigid tip, and no commercial product has been put on the market.
An object, therefore, of the present invention is to provide a practically feasible radial scan, forward viewing ultrasonic endoscope that can minimize the length of the rigid tip of the insertion portion.
This object of the invention can be attained by a radial scan, forward viewing ultrasonic endoscope having an ultrasonic probe that is formed in annular shape to permit radial scan and which is provided at the forward end of an insertion portion, and a forward end portion body that is fitted with objective optics for examining the area ahead of the insertion portion and which has a smaller outside diameter in the front half which is fitted into the ultrasonic probe, wherein a plurality of flexible substrates for transmitting signals to and from the ultrasonic probe extend rearward from the ultrasonic probe, a flexible substrate passage hole of an arcuate cross-sectional shape through which the flexible substrates pass is formed in the front end portion body in an axial direction, and the wirings on the flexible substrates are connected to a signal cable passing through the insertion portion.
In a preferred embodiment, at least one area of the flexible substrate passage hole is divided into portions in a circumferential direction. In another preferred embodiment, a nut member for urging and fixing the ultrasonic probe against the front end portion body from the front meshes with the outer circumferential surface of the distal end portion of the front end portion body.
This object of the invention can also be attained by a radial scan, forward viewing ultrasonic endoscope having an ultrasonic probe that is formed in annular shape to permit radial scan and which is provided at the front end of an insertion portion, and a front end portion body that is fitted with objective optics for examining the area ahead of the insertion portion and which has a smaller outside diameter in the front half which is fitted into the ultrasonic probe, wherein a plurality of flexible substrates for transmitting signals to and from the ultrasonic probe are arranged in arcs around the longitudinal axis of the ultrasonic probe and allowed to pass through the front end portion body and a rotation preventing member for preventing relative rotation of the ultrasonic probe and the front end portion body around the longitudinal axis is provided in a position in that area of a circumferential extension of the series of arcs where no flexible substrate is provided.
In a preferred embodiment, the rotation preventing member is independent of both the ultrasonic probe and the forward end portion body and a groove into which the rotation preventing member is to be fitted is formed in each of the ultrasonic probe and the front end portion body.
This object of the invention can also be attained by a radial scan, forward viewing ultrasonic endoscope having an ultrasonic probe that is formed in annular shape to permit radial scan and which is provided at the front end of an insertion portion, a front end portion body that is fitted with objective optics for examining the area ahead of the insertion portion and which has a smaller outside diameter in the front half which is fitted into the ultrasonic probe, and an inflatable balloon provided to surround the ultrasonic probe, wherein a plurality of flexible substrates for transmitting signals to and from the ultrasonic probe are arranged in arcs around the longitudinal axis of the ultrasonic probe and allowed to pass through the front end portion body and fluid channels that communicate into the balloon are provided in a position in that area of a circumferential extension of the series of arcs where no flexible substrate is provided.
The present disclosure relates to the subject matter contained in Japanese patent application Nos. 2000-136730, 2000-136731 and 2000-136732 (all filed on May 10, 2000), which are expressly incorporated herein by reference in their entireties.